What is translational velocity??? (1 Viewer)

[04er]

Jacaranda doesn't say what it is (instead it talks about radial velocity, proper motion and 'real' velocity), excel and macquarie say it is measured by the doppler effect, physics contexts 2 says it is the 'proper motion' = me confused!

HELP ME PLEASE!

 

[Zarathustra]

I think it is just the velocity of the celestial object, relative to an Earth observer. The moon's translational velocity would be how fast it is moving around the Earth.

Found this: Translational Motion
If the spectral lines in a star's spectrum are uniformly redshifted this would indicate relative recessional motion between the observer and the star. The amount of redshift would depend on the recession velocity. A complicating factor is the fact that the motion may not be directly away from us. In this case the Doppler shift of lines would depend on the component of velocity away from us, that is the star's radial velocity.

A star moving towards us would, of course, exhibit a blueshift in its spectral lines.

 

[04er]

what is the difference between translational and radial velocity?

 

[04er]

Translational is in a straight line for example, and orbit around a star is an example.

Rotational velocity is ho fast the body rotates around its own axis

thank you for replying! When you say translational velocity is in a straight line, does that mean, from our point of view (e.g. it might appear to be moving to the left) or the actual motion of the star relative to us (as in, the resultant velocity)?

 

[BlackJack]

I believe translational velocity would be the actual motion of the star relative to us. Not that I did astro, but this is the most likely.